Automatic lighting control for portrait studio film copying - by photographing grey panel at least once per film and using grey values as standard values in copying light calculations

摘要

At least once per film a standard grey panel is photographed to record the actual studio lighting conditions. The grey panel is provided with a marking identifiable by the sensor of a film copying machine. During analysis of the copies of the film the latter is identified as studio film from the grey panel and the measured grey values are used as standard values for the copying light calculations. Pref. the grey panel has at least three shades of grey, and the marking on the panel is on the leading or trailing edge in film running direction and is in the form of a bar code or a coloured border pref. of an unusual colour. Pref. the detection of the marking by the copying machine sensor produces a signal which sets up the machine for studio portrait processing. ADVANTAGE - Ensure colour-correctness despite disturbance such as lighting spot checks.